Radioactive wastewater produced in the field of nuclear industry has been processed by conventional methods including flocculating settling, sand filtration, diatomaceous earth filtration, ultrafiltration, selective ion exchange, reverse osmosis membrane treatment, evaporation, and electrodialysis.
Each of these methods has its own application scopes and technical characteristics. The current studies mainly focus on the study of decontamination efficiency of various treatments for radioactive wastewater under the condition of reactor core melting down, as well as on the selection of suitable techniques for processing radioactive wastewater according to processing flow and process characteristics.
One goal when processing technology of radioactive wastewater is to increase the decontamination factor of radioactive wastewater, so that the concentration of radionuclide in discharged water is as low as possible and the volume of the concentrate obtained after wastewater treatment and containing radionuclide (simply referred to as “radioactive concentrate”) is as small as possible. Existing membrane systems for processing radioactive wastewater have relatively high decontamination factor, however, their very low concentration multiples (usually merely 5-10) limit their use. At the same time, conventional reverse osmosis treatment systems have strict requirements on water supply, which also significantly limits their uses. If some pretreatments such as diatomaceous earth filtration are applied, the amount of the resulting solid waste would be significantly increased.